Amine Zaoui

Validation of a computer-assisted method for measurement of radiographic wear in total hip arthroplasty using all polyethylene cemented acetabular components

Although cemented all polyethylene (PE) cups have been routinely used in total hip arthroplasty for decades, no computer‐assisted method for measurement of radiographic wear has ever been specifically validated for these implants. Using a validated hip phantom model, AP plain hip radiographs were obtained consecutively for eight simulated wear positions. A version of Martells Hip Analysis Suite software dedicated to all polyethylene sockets was used by three different examiners of varied experience. Bias (mean, standard deviation and 95% confidence interval limit), repeatability (standard deviation and 95% limit) and reproducibility (standard deviation and 95% limit) for two‐dimensional wear measurements were assessed, as recommended by the current ASTM guidelines. Using this protocol, the dedicated software showed an overall mean bias of 0.089 ± 0.060 mm (mean ± SD), and 0.118 mm for 95% CI limit. Repeatability (intra examiner) standard deviation and 95% limit were respectively 0.106 mm and 0.292 mm. Reproducibility (inter examiner) standard deviation and 95% limit were respectively 0.112 mm and 0.308 mm. Martell Hip Analysis for all PE cemented cups is a reliable and low‐cost instrument in the assessment of wear, despite being less precise than its original version dedicated to cementless components.

Biological reaction to polyethylene particles in a murine calvarial model is highly influenced by age

Particle‐induced osteolysis is driven by multiple factors including bone metabolism, inflammation, and age. The objective of this study was to determine the influence of age on polyethylene (PE) particle‐induced osteolysis in a murine calvarial model comparing 2‐month‐old (young) versus 24‐month‐old (old) mice. After PE particle implantation, calvaria were assessed at days (D) 3, D7, D14, and D21 via chemoluminescent imaging for inflammation (L‐012 probe). In addition micro‐computed tomography (micro‐CT) and histomorphometry end points addressed the bone reaction. Inflammation peaked at D7 in young mice and D14 in old mice. Using micro‐CT, a nadir of mature bone was recorded at D7 for young mice, versus D21 for old mice. Besides, regenerating bone peaked at distinct timepoints: D7 for young mice versus D21 for old mice. In the young mice group, the histomorphometric findings correlated with micro‐CT regenerating bone findings at D7, associated with ample osteoïd deposition. No osteoïd could be histologically quantified in the old mice group at D7. This study demonstrated that the biological reaction to polyethylene particles is highly influenced by age.